Flashing light for signalling



7, 1957 c. CRADDOCK 2,804,611

FLASHING LIGHT FOR SIGNALLING Fiied March, 26, 1956 INVENTOR. Claw/a554Cgpopoc/ United States Patent ice FLASHING LIGHT FOR SIGNALLHNG CharlesL. Craddock, North Hollywood, Calif.

Application March 26, 1956, Serial No. 573,848

3 Claims. (Cl. 340366) My invention relates generally to signallingsystems, and more particularly to systems of this type utilizing anelectrically operated flashing light.

The need often arises for a signalling means which will provide aWarning, or draw attention to a particular location. Several deviceshave been used for this purpose, including brilliantly coloredmaterials, reflectors, and various types of flares. Each of thesedevices, however, is somewhat unsatisfactory in certain situations. Theyare either inadequate to gain attention, or they require fuel in whichevent the signal provided is relatively short lived.Electrically-operated signals, as lamps, have therefore been preferredas a means of providing a long-lived attention-commanding signal.

In order to make such signals more commanding, as well as to decreaseenergy requirements, systems have been devised for causing the signal tobe intermittent in operation. One such prior system for producing anintermittent signal makes use of a magnetically operated pulsingmechanism. The present device operates by utilizing the characteristicof certain materials to change in size with variations in temperature.Such a material is formed into an expansion element whose length isvaried to control an electrode switch. The expansion element is thenarranged to be alternatively heated by an electrical current, and thengiven a cooling period. Intermittent switching is thus accomplished by aheat-operated element.

Such devices operate satisfactorily under normal conditions; however, ifconditions are such that water, or other liquids, may accumulate aboutthe expansion element, then the heat generated in the expansion elementwill be dissipated so rapidly that the element will not be capable ofheating sufliciently to effect switching. in addition, these devices aresomewhat uncertain of operation, if rapidly moving air currents may passaround the expansion element and thereby prevent the element fromrapidly heating.

It is therefore a major object of my invention to provide a signallinglight to attract attention or give a warning by intermittent operation,which will be more reliable in operation.

Another object of my invention is to provide a system of this type inwhich intermittent signals will be given in spite of certain adverseconditions as shock, cold, or water.

It is a further object of my invention to provide a signalling systemwhich is rugged, simple, and economical, and which operates morereliably.

These and other objects and advantages of my invention will becomeapparent from the following description of,the preferred form thereof,and from the drawings illustrating that form in which:

Figure l is a ictorial view of a signalling light constructed inaccordance with the principles of my invention.-

Figure 2 is a cross-sectional view of the signalling light illustratedin Figure 1.

Figure 3 is a schematic wiring diagram of a system which may be used inthe practice of my invention.

Referring now to the drawings and particularly to Figure 1 thereof, thenumeral 10 designates a lamp, which will be operated in an intermittentfashion as a signalling means. The lamp 10 is mounted in a socket 11,which is rigidly held by being embedded in a wall of a base 12. Alsosupported by being embedded within the wall of the base 12 are mountingbrackets 13 and 14. The enclosure 12 is preferably formed of a toughmaterial, such as some of the synthetic plastics, and acts as the bodyor principal member of the signalling device. Various members are castor embedded in the base 12, such as the socket 11, previously mentioned,electrical elements hereinafter described, and the mounting brackets 13and 14 that are positioned to receive screws 15 and 16, which hold alamp cover 17 in position. The lamp cover 17 provides protection for thelamp 10, and may be formed of plastic or other transparent ortranslucent material that is so formed as to provide a waterproof andgas-proof connection to the base 12, as by a rabbeted joint. The lampcover 17 may be formed of a colored material to provide a colored-lightsignal, or may be formed so as to be transparent or translucent only incertain areas to thereby provide a directional signal. A lens orrefracting element 17:; may be formed as a part of the cover 17 when sodesired.

The base 12 contains certain electrical circuitry, which will be laterdescribed, and which is connected to a battery 18 for power. The battery18 may be a six volt dry cell type, for example, and may or may not beprovided with an additional protective covering.

in Figure 2, I have illustrated a cross-sectional view of the system,and as shown in that view, prongs 19 and 20, carried by the base 12, areadapted to be inserted in the battery 18, to provide energy for theoperation of the system. The prong 19 is connected to a lug 21, by meansof a lead wire 22. The lug 21 is in turn attached to a contact 23, whichis in direct electrical connection with the bottom terminal of the lamp10. The threaded terminal of the lamp 10 makes contact with the socket11, which is mounted in electrical connection upon the bracket 24, whichis in turn connected by means of a screw 25 to the bracket 14. Thebrackets 14 and 24 are connected by the screw 25 to an arm 26, locatedwithin a flasher element 34, the arm carrying one of the electricalcontacts 27. The other of the contacts 27 is carried by an arm 28,likewise within the flasher element 34, which is attached to the bracket15 by a screw 29. The screw 29 also connects a lead wire 30 from theprong 20 to the arm 28.

The arm 23 is formed of a metal spring material, and is held in a flexedposition by an expansion element, i. e., resistance wire 31. Theresistance wire 31 is mounted in tension between studs 32 and 33, whichare composed of electrical-insulating material. The resistance wire 31is electrically connected between the arms 28 and 26. The materialforming the resistance wire 31 has a high electrical resistance, and apositive coefficient of heat expansion. Thus when the resistance Wire 31is heated, it will increase its length, and allow the flexed arm 27 tostraighten out and thereby close the contacts 27.

The electrical circuit of the described embodiment is shownschematically in Figure 3. The battery 18 has its positive terminalconnected by wire 30 to a parallel cir cuit, within the flasher element34, comprising the resistance wire 31 and the contacts 27, mounted onthe arms 26 and 28. The parallel circuit is then connected by bracket 24through the lamp 10 to the negative terminal of the battery 18 by wire22.

At the time when the system is first energized, the contacts 27 will bein an opened position due to the ,flexed position of the arm 28. Duringthe following Patented Aug.. 27, 1957- interval an electrical currentfiows from the positive terminal of the battery 18, through theresistance wire 31, the lamp 10, and back to the negative terminal ofthe battery 18. This current is small due to the high resistance of theresistance wire 31, which is much higher than the resistance of thelamp. 10. Such a current is therefore not sufficient to cause thefilament of the lamp to glow, and therefore no light will emanate fromthe signal during this time. After a short interval the current passingthroughthe resistance wire 31 will heat the resistance wire 31 therebycausing it to expand. With the expansion of the resistance wire 31, thearm 28, which is; normally held in a figted position, will be allowed tostraighten to some extent, thereby closing the contacts 27 With the.closure of the contacts 27, the resistance wire, 31; is shuntedelectrically by a low resistance path through, the contacts; 27. Duringthe period when the contacts 27 are closed, a circuit will be completedfrom the, battery 18: through the contacts 27 and the lamp 10, "and thecurrent flowing through the circuit will be sufficientto cause thefilament of the lamp 10 to glow. As essentially no current flows throughthe resistance wire 31 duringthisinterval, it will cool, and willcontract in length to again flex the arm 28 and open the contacts 27.When the contacts 27 are again opened, the current through the lamp 10will again be reduced to an amount inadequate to cause the filament toglow. This cycle will then repeat as the resistance wire 31 effectsautomatic circuit-interrupter,operation, to intermittently operate thelamp 10.

The reliability of the operation as described above depends to a largeextent upon the resistance wire 31 being heated when an electricalcurrent is passed through it, and permitted to cool when no electricalcurrent is passed through it. If the rate of heat transfer from the Wire31 is materially changed, the operation will likewise be changed; If'thewire 31 loses heat too rapidly, the contacts '27 may never close, or itclosed, will open too soon. If the wire 31 loses heat too, slowly, thecontacts 27; once closed, may not open, or may open for too short atime. To prevent these undesirable effects, the flasher element 34 ismounted in a housing which in turn is embedded in the plastic base orenclosure 12. In this way the desired thermal and" electrical insulationis achieved.

The cover 17 makes a water-tight and gas-tight seal with the hase 12,and the resulting unit will operate dependably ir 1 all kinds. ofweather. Even if the entire unit issubmerged ina puddle of rain water,it will continue .to operate until the disintegration of the battery 18causes a, failure, of the power source. Likewise, being sealed, theunitmay. operate in explosive atmosphere where normal flashing lights areprohibited. Should the bulb 10 born out, it can easily be replaced byremoving the cover 17, and it will be-appreciated that the battery 18can be replacedjn a matter of seconds by merely unplugging the unitfromone battery and plugging it into another. In this connection, thesimplicity of connecting the unit to a. power source eliminates the needfor a separate switch, thereby simplfying manufacture and reducing cost.

The flasher element 34 is a standard article of commemo that has provendependable over an extended period of time. No claim is made to theflasher element 34. by and ofitself, but only :as it may be combinedwith other devices and elements to provide a complete combination.

Erom. the foregoing, it will be apparent to those skilled in the artthat I have provided a greatly improved and very satisfactory signallinglight fully capable of achieving;the o bjects and advantageshereinbefore set forth. It

will be apparent, however,'that'variations may be made exact method ofconnection herein described and shown, except as limited by my claims.

I claim:

1. A signal light of the class described which includes: an electricallyoperated source of light; an electrically operated thermally actuatedelectrical circuit interrupter; connector means adapted tov makeelectrical connection to a source of power; conductor means establishinga series electrical circuit from one of said connector means, throughsaid interrupter, through said source of light, and to another of saidconnector means; encasing means of thermally and electrically insulatingmaterial enclosing said interrupter and said conductor means and :aportion of said connector means to form a unitary structure in whichsaid connector means project from one side of said structure and saidlight source projects from another side, said structure sealing all ofthe elements therein from external fluids; and protective means ofgenerally transparent material making a sealing fit with said encasingmeans and enclosing said light source, said protective means forming acontinuation of said encasing meansand with said encasing means forminga unitary light and flasher combination in which all elements except apower source are sealed and encased within a unitary structure.

2. A signal light of the class described which includes: an electricallyoperated source of light; an electrically operated electrical circuitinterrupter of the type actuated by the generation of heat caused by thepassage of current through said interrupter; connector means adapted tomake electrical connection to a source of power; conductor meansestablishing a series electrical circuit from one of said connectormeans, through said interrupter, through said source of light, and toanother of said connector means; encasing means of thermally andelectrical insulating material enclosing said interrupter and saidconductor means and a portion of said connector means to form a unitarystructure in which said connector means project from one side of saidstructure and said light source projects from another side, saidstructure sealing all of the elements therein from external fiuids andthermally insulating said interrupter from the eflects of external heatand temperature; and protective means of generally transparentmaterialmaking a sealing fit with said encasing means and enclosing saidlight source, said protective means forming a continuation of saidencasing means and with said encasing means forming a unitary light andflasher combination in which all elements except a power source aresealed and encased within a unitary structure.

3. A signal light of the class described, adapted to be plugged into abattery having a socket or plug-receiving jack, and to form a unitarystructure therewith, including: an electrically operated source oflight; an electrically operated electrical circuit interrupter of thetype actuated by the generation of heat caused by the passage of currentthrough said interrupter; a pair of connector means in the form of plugsspaced to fit into the jacks of said battery to complete a circuitthereto; conductor means establishing a series electrical circuit fromone of said connector means, through said interrupter, through saidsource of light, and to another of said connector means; encasing meansof thermally and electrically insulating material enclosing saidinterrupter and said conductor means and a portion of said connectormeans to form a unitary structure in which said connector means isfirmly held to said structure and projects from one side thereof toenter the jacks of the battery to hold said structure to said battery,said light source projecting from another side of said structure, all ofthe said elements within said structure being sealed by the, latter fromexternal fluids, said encasing means thermally insulating saidinterrupter from the effects of external heat and temperature; andprotective means of generally transparent material making a sealing fitwith said encasing means and enclosing said References Cited in the fileof this patent UNITED STATES PATENTS Shaw June 12, 1923 Abrahamson Mar.30, 1954 Trempe July 20, 1954

